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39
40//
41// W A R N I N G
42// -------------
43//
44// This file is not part of the Qt API. It exists purely as an
45// implementation detail. This header file may change from version to
46// version without notice, or even be removed.
47//
48// We mean it.
49
50#ifndef Patternist_RangeIterator_H
51#define Patternist_RangeIterator_H
52
53#include <private/qitem_p.h>
54
55QT_BEGIN_NAMESPACE
56
57namespace QPatternist
58{
59 /**
60 * @short RangeIterator represents a sequence of integers between a
61 * start and end value.
62 *
63 * The RangeIterator contains the evaluation logic for the range expression, <tt>N to M</tt>,
64 * and its behavior is therefore consistent with the definition of that XPath expression.
65 * Hence, the detailed behavior of the RangeIterator can be found in the XPath 2.0
66 * specification.
67 *
68 * @see <a href="http://www.w3.org/TR/xpath20/\#doc-xpath-RangeExpr">XML Path Language
69 * (XPath) 2.0, 3.3 Sequence Expressions, RangeExpr</a>
70 * @see RangeExpression
71 * @author Frans Englich <frans.englich@nokia.com>
72 * @ingroup Patternist_iterators
73 * @todo Documentation is missing
74 */
75 class Q_AUTOTEST_EXPORT RangeIterator : public Item::Iterator
76 {
77 public:
78
79 /**
80 * RangeIterator can iterate in both directions.
81 * This enumerator exist for identifying different directions.
82 */
83 enum Direction
84 {
85 /**
86 * Signifies that the QAbstractXmlForwardIterator operates in a reverse direction, where the
87 * first item returned by the next() function is from the beginning of the
88 * source sequence.
89 */
90 Backward = 0,
91
92 /**
93 * Signifies the forward direction. Iterators do conceptually operate
94 * in the forward direction by default.
95 */
96 Forward = 1
97 };
98
99 /**
100 * Creates an QAbstractXmlForwardIterator that returns integer values from consecutive sequence
101 * of integers between @p start and @p end, where the step taken
102 * between each integer is 1 with polarity as specified in @p direction.
103 *
104 * @note @p start must be smaller than @p end, not larger
105 * or equal. This is not checked.
106 */
107 RangeIterator(const xsInteger start,
108 const Direction direction,
109 const xsInteger end);
110
111 virtual Item next();
112 virtual Item current() const;
113 virtual xsInteger position() const;
114 virtual xsInteger count();
115 virtual Item::Iterator::Ptr toReversed();
116 virtual Item::Iterator::Ptr copy() const;
117
118 private:
119 xsInteger m_start;
120 xsInteger m_end;
121 Item m_current;
122 xsInteger m_position;
123 xsInteger m_count;
124 const Direction m_direction;
125
126 /**
127 * We only need to store -1 or 1, so save memory with a bit field.
128 */
129 const qint8 m_increment : 2;
130 };
131}
132
133QT_END_NAMESPACE
134
135#endif
136

source code of qtxmlpatterns/src/xmlpatterns/iterators/qrangeiterator_p.h